Objects to be weighed, such as detergents and confectionary, which are weighed by a combination weigher to have a predetermined weight, are typically packaged by a packaging machine. A schematic construction of a conventional combination weigher which weighs objects to be weighed is shown in FIG. 12. In addition, a schematic construction of the packaging machine disposed below the combination weigher is shown in FIG. 13.
The combination weigher shown in FIG. 12, whose operation is entirely controlled by a control unit 20, is provided with a dispersion feeder 1 at the center of an upper part of the combination weigher. The dispersion feeder 1 has a conical shape and serves to radially disperse objects to be weighed supplied from an external supplying device by vibration. Around the dispersion feeder 1, linear feeders 2 are provided to transfer the objects to be weighed sent from the dispersion feeder 1 into the corresponding feeding hoppers 3 by vibration. The plurality of feeding hoppers 3 and weighing hoppers 4 are disposed below the linear feeders 2 and are arranged circularly in such a manner that each feeding hopper 3 and each weighing hopper 4 correspond to the associated one of the linear feeders 2. The feeding hoppers 3 receive the objects to be weighed transferred from the linear feeders 2 and open their gates when the weighing hoppers 4 disposed therebelow become empty to feed the objects to be weighed to the weighing hoppers 4. Weight sensors 41 such as load cells are attached to the weighing hoppers 4, and measure the weight of the objects to be weighed inside the weighing hoppers 4. The control unit 20 performs combination calculation to select a combination of hoppers to discharge the objects to be weighed therefrom from the plurality of weighing hoppers 4. The objects to be weighed are discharged from the weighing hoppers 4 corresponding to the combination onto the collecting chute 6. The collecting chute 6 is provided below the weighing hoppers 4. The objects to be weighed discharged from the weighing hoppers 4 slide down on the collecting chute 6, and are sent out from an outlet provided in a lower portion thereof to the packaging machine shown in FIG. 13.
In the packaging machine, bags are manufactured while the objects to be weighed discharged from the combination weigher are charged into the bags and packaged. In this packaging machine a sheet of wrapping material 50 withdrawn from a roll of a wrapping material is caused to be wound around a tube 51 by a former 52 to form a cylindrical shape and is suctioned by a pulldown belt 53 to be transferred downwardly, and the superposed vertical edges of the cylindrical wrapping material 50 are sealed (sealing by fusion adhesion) by a vertical sealing machine 54. The objects to be weighed which have been weighed are then charged into the cylindrical wrapping material 50 through the tube 51, and a horizontal sealing machine 55 disposed below the tube 51 seals horizontally across the upper end of a preceding bag and the lower end of a following bag (sealing by fusion adhesion). By this horizontal sealing, the preceding bag is completed with its upper and lower ends sealed since the lower end of the preceding bag has been sealed by the previous horizontal sealing. The center of the horizontally sealed portion is then cut by a cutter built in the horizontal sealing machine 55 so that the preceding bag and the following bag are separated from each other.